Neco 2018 Biology Question 4

Practice practical question 4 from the 2018 Neco Biology examination. This question covers Respiration, Rate of respiration .

Neco 2018 Biology Practical
Topics: Respiration Rate of respiration
Question 4 NECO • 2018 • BIOLOGY • practical

A group of students set up a simple closed‑system respirometer to measure the rate of aerobic respiration in germinating beans. The respirometer consists of a sealed container connected to a graduated syringe that records the volume of gas displaced. The experiment was performed at 25 °C. The following data were obtained:

Question Parts

( a )
For the control (no inhibitor) the syringe showed a displacement of 4.8 mL of gas in 5 minutes. Calculate the rate of respiration in mL CO₂ min⁻¹.
( b )
When 0.5 mL of 0.1 M potassium cyanide (KCN) was added to a second identical set‑up, the gas displacement after 5 minutes was only 1.2 mL. Calculate the respiration rate for the inhibited sample and the percentage inhibition relative to the control.
( c )
Explain, in biochemical terms, why cyanide reduces the rate of respiration observed in the respirometer.
( d )
State two precautions that should be observed when performing this experiment and two sources of error that could affect the results.

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About This Question

This is Neco 2018 Biology Question 4. It is one of the practical questions from the 2018 Neco Biology examination.

The question covers Respiration, Rate of respiration .

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